A two-year project is propose to provide support for the analysis of data that were collected, but not processed in an earlier four-year project designed to investigate parent and sibling influence on adolescent drug-use (DA 03706). The aims of the initial project were to (a) determine the extent of parent and sibling influence on adolescent drug-use decisions and to evaluate the relative strength of these sources of influence; (b) To elucidate the specific mechanisms or processes by which families influence their children's use of cigarettes, marijuana, alcohol, and smokeless tobacco; and (c) To relate observational data on family interactions to the use of cigarettes, marijuana, alcohol and smokeless tobacco. Comprehensive self-report questionnaires were administered annually, for three years, to all family members over the age of 11 and still living at home in a sample of 763 families. In addition, the study included three components which allowed more intensive investigation of the social processes that contribute to the acquisition and maintenance of substance use. A subset of 17% of the families was selected to participate in (a) videotaped parent-adolescent problem-solving interactions, and (b) individual face-to- face interviews. In addition, (c) brief telephone probes (interviews) with target adolescents and/or one parent selected from the whole sample were carried out every three months during the first year to provide proximal information about the onset and/or changes in the use of four substances (i.e., cigarettes, alcohol, marijuana, and chewing tobacco) and the factors that may be controlling such changes. Budget cuts made the processing of these data infeasible. While a continuation project has been funded to extend our longitudinal research on these subjects from three to eight years, to include questionnaire measures of the use of hard drugs, and to add the independent measurement of peer factors, provision for the processing and analysis of data from the initial grant was not included. Processing the data noted above would provide additional predictors for assessing the short and longterm consequences of substance use.